Malignant tumors (carcinoma, sarcoma and so on) are diseases which cause serious trouble with life maintenance of body and which have very high fatality rate when patients affect. In general they are classified by organs or tissues they develop from, into colon carcinoma, breast carcinoma, gastric carcinoma, lung carcinoma and bone sarcoma, for example. Histologically they are classified into adenocarcinoma, squamous cell carcinoma, transitional cell carcinoma, anaplastic carcinoma and so on.
Efficacious techniques for diagnosis and treatment against various types of malignant tumors have been developed by each research institution and the like. But valid techniques for diagnosis and treatment are not established in many cases.
Squamous cell carcinoma is a cancer which cells of squamous epithelium or squamous metaplasia are changed into malignant tumors. It appears at buccal cavity, tongue, vocal cord, esophagus, tracheobronchial region, lung, pharynx, larynx, female valuva, vagina, cervix, vaginal portion, skin, anus and so on. It occurs comparatively with increased frequency. For example, about 30% of lung carcinomas and about 90% of esophageal carcinomas are squamous cell carcinomas. Also about 80% of uterine carcinomas are cervical carcinomas and most of them are squamous cell carcinomas.
Transitional cell carcinoma is a cancer which cells derived from transitional epithelia tissues changed into malignant tumors. It appears at renal pelvis, urinary duct, bladder and so on.
Adenocarcinoma is a cancer which cells derived glandular tissues changed into malignant tumors. It appears at lacteal gland, stomach, colon, lung, gall bladder, bile duct, kidney, prostate, duodenum, pancreas, ovary, uterus, vagina and so on.
In skin cancer, basal cell carcinoma, squamous cell carcinoma and melanoma in turn appear with increased frequency. In head and neck cancer, most of tongue cancers are squamous cell carcinomas, in pharynx cancer, squamous cell carcinoma and malignant lymphoma appear with increased frequency, and most of larynx cancers are squamous cell carcinomas. In lung cancer, adenocarcinoma, squamous cell carcinoma, small cell carcinoma in turn appear with increased frequency. Most of esophaus cancers are squamous cell carcinomas, most of gastric cancers and colon cancers are adenocarcinomas, and most of pancreas cancers are tubular adenocarcinomas. Most of uterus cancers are adenocarcinomas, most of cervix cancers are squamous cell carcinomas, and most of breast cancers are adenocarcinomas. In kidney cancers, renal cell carcinomas (adenocarcinomas) and renal pelvis-ureter carcinomas (transitional cell carcinomas) in turn appear with increased frequency. Most of bladder cancers are transitional cell carcinomas and part of them are squamous cell carcinomas.
Each cancer is diagnosed by histopathological examination (biopsy, cytodiagnosis, tissue diagnosis, etc), CT (computerized tomography), PET (positron emission tomography), endoscopical ultrasonography and so on. However it is preferable to establish more accurate diagnostic techniques, for example, in regard to detection of with or without invasion and metastasis, and clarity of the cancerous or noncancerous boundaries. Also, operative therapy, chemical therapy or radiation therapy are treated for patients of each squamous cell carsinomas, but sufficient therapeutic effects have not been obtained in many cases.
GPCRs (G-protein-coupled receptors) are membrane proteins with seven transmembrane domeins, and are estimated to constitute a superfamily of nearly 1,000. Their ligands are diverse, for example, exogenous stimulations (lights, smells, tastes, pheromone, etc), lipids, hormones, autacoid, neurotransmitters, nucleotides and so on. In addition, it is thought that more than half of the drugs that are currently available act on GPCR.
GPR87 (G protein-coupled receptor 87) is a protein belonging to the GPCR family, its gene has homology with some of the P2Y receptor, but its function and other knowledge are poorly understood. In non-patent document 1, it was reported that the GPR87 gene has been identified by EST data mining. In non-patent document 1, it was reported that the ligand of GPR87 is lysophosphatidic acid.
It is known by microarray analysis that GPR87 has relatively high expression at the RNA transcriptional levels in skin and placenta of normal human tissues, in small airway epithelial cells, tracheal bronchial epithelial cells, epidermal keratinocytes and human prostate epithelial cells of normal human cells, in lung carcinomas (squamous cell carcinomas) and pancreatic carcinomas of cancer tissues, and cell lines derived from human esophageal carcinoma, cell lines derived from human gastric carcinoma, cell lines derived from human pancreatic carcinoma, cell lines derived from human lung carcinoma, cell lines derived from human ovarian carcinoma, and cell lines derived from human cervical carcinoma of carcinoma's cell lines.
In non-patent document 3, it was reported that GPR87 expresses highly in lung squamous cell carcinoma. In non-patent document 4, it was reported that GPR87 expresses in lung squamous cell carcinoma, lung adenocarcinoma, head and neck carcinoma, pharynx squamous cell carcinoma, larynx squamous cell carcinoma, skin squamous cell carcinoma and cervical squamous cell carcinoma, and it may contribute to viability of human tumor cells.
In patent document 1, GPR87 expression profiles obtained by real-time PCR are disclosed. In addition, the document mentions GPR87 monclonal antibodies, its chimeric antibodies, single chain antibodies and so on, however the actual establishment of hybridomas producing monoclonal antibodies has not been disclosed.
In patent document 2, the anti-GPR87 antibodies for the treatment of cancer are disclosed. In addition, the document mentions GPR87 monclonal antibodies, its modified antibodies, its chimeric antibodies, its humanized antibodies and so on, however only rabbit polyclonal antibodies have been produced and used by them, and the actual establishment of hybridomas producing monoclonal antibodies has not been disclosed.
To date, the anti-GPR87 antibody are sold by Acris Antibodies GmbH (German), Abcam, Inc. (UK), LifeSpan Biosciences, Inc. (USA), Novus Biologicals, LLC (USA), Thermo Fisher Scientific, Inc. (USA), MBL International Corporation (USA), Gene Tex, Inc. (USA), Genway Biotech, Inc. (USA), United States Biological (USA), Imgenex Corporation (USA) and so on. Some of these antibodies were used in the experiments mentioned in non-patent document 3 and non-patent document 4. However these antibodies are all rabbit polyclonal antibodies. To date, it is not reported that GPR87 monoclonal antibodies are actually created.
In non-patent document 5, it has been described about DNA immunization. In non-patent document 6 and 7, it has been described about examples of methods for producing monoclonal antibodies. In non-patent document 8, it has been described about chimera antibodies. In non-patent document 9, it has been described about humanized antibodies. In non-patent document 10 and 11, it has been described about scFv. Non-patent document 5-11 are incorporated into this application by reference. Citation of these documents is not an admission that any particular reference is prior art to this invention.
[Patent Document 1]
    WO2004/082572[Patent Document 2]    WO2008/031842[Non-Patent Document 1]    T. Wittenberger et al, “An Expressed Sequence Tag (EST) Data Mining Strategy Succeeding in the Discovery of New G-Protein Coupled Receptors”; J. Mol. Biol. (2001) 307, 799-813[Non-Patent Document 2]    K. Tabata et al, “The orphan GPCR GPR87 was deorphanized and shown to be a lysophosphatidic acid receptor”; Biochemical and Biophysical Research Communications 363 (2007) 861-866[Non-Patent Document 3]    M. Gugger et al, “GPR87 is an overexpressed G-protein coupled receptor in squamous cell carcinoma of the lung”; Disease Markers 24 (2008) 41-50[Non-Patent Document 4]    S. Glatt et al, “hGPR87 contributes to viability of human tumor cells”; Int. J. Cancer 122, 2008-2016 (2008)[Non-Patent Document 5]    K. K. Peachman et al, “Immunization with DNA through the skin”; Methods 31 (2003) 232-242[Non-Patent Document 6]    G. Galfre and C. Milstein, “Preparation of Monoclonal Antibodies: strategies and Procedures”; Methods in Enzymology 73 (1981) 3-46[Non-Patent Document 7]    St. Groth et al, “Production of Monoclonal Antibodies: Strategy and Tactics”; Journal of Immunological Methods 35 (1980) 1-21[Non-Patent Document 8]    S. L. Morrison et al, “Chimeric human antibody molecules: Mouse antigen-binding domains with human constant region domains”; Proc. Natl. Acad. Sci. USA 81 (1984) 6851-6855[Non-Patent Document 9]    M. Verhoeyen et al, “Reshaping human antibodies: Grafting an antilysozyme activity”; Science 239 (1988) 1534-1536[Non-Patent Document 10]    R E Bird et al, “Single-chain antigen-binding proteins” Science 242 (1988) 423-426[Non-Patent Document 11]    J. S. Huston et al, “Protein engineering of antibody binding sites: recovery of specific activity in an antidigoxin single-chain Fv analogue produced in Escericia coli”; Proc. Natl. Acad. Sci. USA 85 (1988) 5879-5883